For the past year and a half, a killer has been on the loose, taking out millions of starfish up and down the West Coast of North America. By the time it is done with an area, starfish that had once littered the ocean floor have been reduced to mounds of white goo.

The silent killer now appears to be a kind of parvovirus—the group of viruses that cause gastrointestinal problems in unvaccinated dogs—researchers report Monday in the journal Proceedings of the National Academy of Sciences.

Sea stars are linchpins in the ecology of habitats like tide pools, said Robert Paine, a retired marine ecologist at the University of Washington in Seattle, in an interview earlier this